Multi-lumen central access vena cava filter apparatus and method of using same

ABSTRACT

A combined multi-lumen central access catheter and an embolic filter including ports proximal and distal the filter for fluid infusion and/or pressure sensing and infusion ports in the catheter to permit infusion of bioactive agents, flushing agents and/or contrast agents. The embolic filter may be removably coupled to the multi-lumen catheter for temporary placement and retrieval under recommended indications.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/684,839, filed Jan. 8, 2010, which is a continuation-in-part of U.S.patent application Ser. No. 11/849,225 filed Aug. 31, 2007, from whichpriority is hereby claimed. The aforementioned patent applications areincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

The present invention pertains generally to the field of vascularfilters for capturing embolic material in the blood flow.

The accepted standard of care for patients with venous thromboembolism(VTE) is anticoagulant therapy. Inferior vena cava (IVC) filters arereserved for those patients who fail anticoagulant therapy, or have acomplication or contraindication to anticoagulant therapy. Until theearly 1970's, the only method of IVC interruption was surgical, eitherby clipping, ligation or plication. The first clinical experience of anendoluminally-placed device to interrupt IVC flow was reported byMobin-Uddin et al. in 1969. However, it was not until the introductionof a stainless steel umbrella-type filter by Greenfield et al. in 1973that an effective method of endoluminally trapping emboli whilesimultaneously preserving IVC flow became possible. Indeed, for manyyears, the Greenfield filter set a benchmark by which newer filters weremeasured. Early generations of filters were inserted by surgicalcut-down and venotomy. Eventually filters were able to be insertedpercutaneously: initially through large 24 Fr sheaths, though newergenerations of filters are able to be delivered through 6 Fr systems.

Despite the safety and efficacy of modern day filters, systemicanticoagulation remains the primary treatment for VTE. Eitherunfractionated or low molecular weight heparin followed by three monthsof oral anticoagulation in patients with proximal deep venous thrombosis(DVT) is approximately 94% effective in preventing pulmonary embolism(PE) or recurrent DVT. The routine placement of IVC filters in additionto anticoagulation in patients with documented DVT was investigated byDecousus et al. in a randomized trial. Decousus H, Leizorovicz A, ParentF, et al. A clinical trial of vena caval filters in the prevention ofpulmonary embolism in patients with proximal deep-vein thrombosis. NEngl J Med 1998; 338:409-415. This study revealed that the use of apermanent filter in addition to heparin therapy significantly decreasedthe occurrence of PE within the first 12 days compared to those withouta filter. However, no effect was observed on either immediate orlong-term mortality, and by 2 years, the initial benefit seen in thegroup of patients with filters was offset by a significant increase inthe rate of recurrent DVT.

Despite the efficacy of anticoagulant therapy in the management of VTE,there are certain situations and conditions in which the benefits ofanticoagulation are outweighed by the risks of instituting such atherapy. These include contraindications and complications ofanticoagulant therapy. In such circumstances, there may be absolute orrelative indications for filter insertion

Currently, there are eight different types of permanent cava filtersthat are FDA approved. These include the Bird's Nest filter (CookIncorporated, Bloomington, Ind.), Vena Tech LGM filter (B. Braun,Bethlehem Pa.), Vena Tech LP (B. Braun), Simon Nitinol filter (Bard,Covington, Ga.), Titanium Greenfield filter (Boston Scientific, NatickMass.), Over-the-Wire Greenfield filter (Boston Scientific), TrapEasefilter (Cordis Corp.) and the Gunther Tulip filter (Cook Inc.)

Well-founded concerns over the long-term complications of permanent IVCfilters, particularly in younger patients in need of PE prophylaxis witha temporary contraindication to anticoagulation, has led to thedevelopment of temporary and retrievable filters. Temporary filtersremain attached to an accessible transcutaneous catheter or wire. Thesehave been used primarily in Europe for PE prophylaxis duringthrombolytic therapy for DVT. Currently these devices are not approvedfor use in the United States. Retrievable filters are very similar inappearance to permanent filters, but with modifications to the cavalattachment sites and/or hooks at one end that can facilitate theirremoval. Retrievable filters are currently available in the UnitedStates, examples of these include the Gunther Tulip (Cook Inc.), OptEase (Cordis Corp.), and Recovery nitinol filters (Bard PeripheralVascular, Tempe, Ariz.) Lin P H, et al., Vena caval filters in thetreatment of acute DVT. Endovascular Today 2005; January:40-50. The timelimit of retrievability is in part dependant on the rate ofendothelialization of the device, which typically occurs within 2 weeks.However, differences in design may extend the time period in which thefilter may be safely retrieved.

Currently no consensus exists as to which patients have an indicationfor a retrievable filter. However, it is generally accepted thatpatients at high risk for pulmonary embolism or with documented PE andwith a temporary contraindication to anticoagulation are candidates.

Certain circumstances preclude the placement of a filter in theinfrarenal IVC. This includes thrombus extending into the infrarenalIVC, renal vein thrombosis or pregnancy. The safety of suprarenalplacement of IVC filters is well documented, with no reported instancesof renal dysfunction and no differences in the rates of filtermigration, recurrent PE or caval thrombosis.

The rate of upper extremity DVT is on the rise. This is predominantlydue to an increasing number of patients having short- and long-termupper extremity central venous access catheters. In one study, 88% ofpatients found to have an upper extremity DVT had a central venouscatheter present at the site of thrombosis at the time of diagnosis orwithin the previous two weeks. Pulmonary embolism may complicate upperextremity DVT in 12-16% of cases. In patients who have such acomplication or contraindication to anticoagulation, a filter can besafely placed immediately below the confluence of the brachiocephalicveins. However, misplacement of an SVC filter is theoretically morelikely than with an IVC filter because of the relatively short targetarea for deployment.

The most common imaging modality used for filter insertion isfluoroscopy, performed either in an interventional suite or an operatingroom. Bedside placement of filters has inherent advantages, particularlyfor critically ill patients in intensive care settings where transportcan be avoided. Portable fluoroscopy, surface duplex ultrasound andintravascular ultrasound (IVUS) have all been used to assist withbedside filter placement.

Vena cava filter placement frequently occurs concomitantly with centralaccess line placement or in critically ill patients that already have acentral access line in place. Heretofore, however, there have been nodevices which combine the function of a central access catheter and aremovable vena cava filter.

SUMMARY OF THE INVENTION

A multi-lumen central access catheter comprises a proximal end and adistal end thereof relative to the longitudinal axis of the catheter, avena cava filter near the distal end of the central access catheter, atleast one of a port proximal the vena cava filter or a port distal thevena cava filter and plural fluid infusion ports passing through wallsof the central access catheter and positioned to deliver fluid to aspace delimited by the vena cava filter. The plural fluid infusion portsare positioned in the walls of the central access catheter and have adirectional flow orientation such that any or all regions of the spacedelimited by the vena cava filter may be exposed to fluid flow therefrom. The proximal and distal ports, which may be positioned entirely orpartially distant from an open area bounded by the filter member, permitmeasuring pressure and/or flow velocity across the filter as adeterminant of extent of capture of embolic material in the filter orfor measuring flow rate at the position of the filter member as apositional indicator within the body. Pressure or flow sensing may beaccomplished by a hydrostatic fluid column in communication with each ofthe proximal and distal ports and a pressure transducer operablyassociated with a proximal end of the central access catheter.Alternatively, pressure or flow sensors may be disposed either withinthe proximal and distal ports or within lumens communicating with theproximal and distal ports. Preferably, the proximal and distal ports,and lumens associated therewith, are also open to fluid flow to providemeans for introducing fluids, such as an anticoagulant, thrombolytic orother bioactive agents, contrast medium, blood transfusions, intravenousfluids or other medications. Alternatively, the proximal and distalports may be used for withdrawal or evacuation of fluids or othermaterial through the catheter. The multiple infusion ports also providea means for introducing a flushing medium, such as saline, underelevated pressure to produce mechanical thrombolysis or inducethrombolysis by the infusion of thrombolytic agents directly to thrombuswithin the filter.

The present invention may be configured for either a femoral approach ora jugular approach to the inferior vena cava. Vena cava filters aretypically deployed infrarenaly, but may also be deployed suprarenaly. Itwill be understood that within the inferior vena cava blood flow issuperior, i.e., toward the patients head. Thus, in all embodiments, thevena cava filter will be positioned so that it opens inferiorly, i.e.,away from the patient's head and toward the direction of the blood flow.It will be appreciated, therefore, that in the present invention, thevena cava filter will have a different axial orientation on the centralaccess catheter depending upon whether the device is intended for use ina femoral approach or a jugular approach.

Accordingly, it is an objective of the present invention to provide amulti-lumen catheter coupled to a vena cava filter that is useful bothas a central venous access catheter for administration of intravenousfluids, bioactive agents, contrast agents, flushing agents, pressurizedfluids for mechanical thrombolysis and/or withdrawal of blood samplesand for capture of thrombus or emboli.

Another aspect of the present invention is to provide a filter geometryin which the proximal portion of the filter, relative to the axis ofblood flow, has larger interstitial openings to permit thrombus orembolic material to flow into the filter, while the distal portion ofthe filter, again relative to the axis of blood flow, has relativelysmaller interstitial openings that capture the thrombus or embolicmaterial within the filter. Another way to view this aspect is that thestructure of the filter includes a greater open surface area exposed tothe flow of embolic material into the filter at its proximal end, whilethe distal end has smaller open surface area exposed to the flow ofembolic material to capture the embolic material in the distal end ofthe filter member. More specifically, regardless of whether the presentinvention is delivered by a jugular approach or a femoral approach, thefilter geometry is such that the larger interstitial openings of thefilter are positioned inferiorly along a longitudinal axis of thefilter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a central venous access vena cava filtercatheter in accordance with a first embodiment of the present inventionwith the vena cava filter in an unexpanded state.

FIG. 2 is a side elevational view of a central venous access vena cavafilter catheter in accordance with the first embodiment of the presentinvention.

FIG. 3. is a cross-sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 2.

FIG. 6 is a perspective view of a central venous access vena cava filtercatheter in accordance with a second embodiment of the present inventionillustrating the vena cava filter in an unexpanded state.

FIG. 7 is a side elevational view of a central venous access vena cavafilter catheter in accordance with the second embodiment of the presentinvention.

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7.

FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 7.

FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. 7.

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 7.

FIG. 12 is a perspective view of the central venous access vena cavafilter catheter of FIG. 1 illustrating the vena cava filter in adiametrically expanded state.

FIG. 13A is a perspective view of a vena cava filter member inaccordance with a first embodiment thereof.

FIG. 13B is a first side elevational view thereof.

FIG. 13C is an end elevational view thereof.

FIG. 13D is a second side elevational view thereof.

FIGS. 14A-14H are perspective views of alternative embodiments of a venacava filter member in accordance with the present invention.

FIG. 15A-15H are fragmentary side elevational views of the alternativeembodiments of the vena cava filter member illustrated in FIGS. 14A-14H.

FIG. 16A is a side elevational view of the vena cava central linecatheter in its undeployed state.

FIG. 16B is a side elevational view of the vena cava central linecatheter in its deployed state.

FIG. 17 is a side elevational view of an vena cava filter member in itsexpanded state in accordance with one embodiment of the presentinvention.

FIG. 18 is a perspective view of a vena cava filter member in itsexpanded state in accordance with an alternative embodiment of thepresent invention.

FIG. 19 is a perspective view of a vena cava filter member in itsexpanded state in accordance with yet another embodiment of the presentinvention.

FIG. 20 is a perspective view of a vena cava filter member in itsexpanded state in accordance with still another embodiment of thepresent invention

FIGS. 21A and 21B are perspective views of a vena cava filter membermounted at a distal end of a central line catheter having a distalballoon.

FIGS. 22A and 22B are perspective views of an alternative embodiment ofa vena cava filter member mounted at a distal end of a central linecatheter having a distal balloon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the accompanying Figures like structural or functional elements aredesignated by like reference numerals, e.g., 16, 116, 216, 316, 416represent similar structural or functional elements across differentembodiments of the invention. With particular reference to FIGS. 1-5,according to a first embodiment of the invention, there is disclosed acentral venous access filter (“CVAF”) 10 that is composed generally of amulti-lumen central venous access catheter body 12 having a proximalport 32 associated with a first lumen 44 and a distal port 34 associatedwith a second lumen 42, a filter member 16, having a first end 18 and asecond end 20, is positioned generally intermediate the distal port 34and the proximal port 32 and is generally concentric relative to thecatheter body 12. An outer sheath 22 is concentrically disposed over thecatheter body 12 such that relative movement of the catheter body 12 andthe outer sheath 22 either exposes the filter member 16 or captures thefilter member 16 within the outer sheath 22. The outer sheath 22terminates in an annular opening at a distal end thereof and at firsthub member 225 as depicted in FIGS. 16A and 16B. The proximal hub 225will be described more fully hereinafter. The catheter body 12 extendsthrough a central bore in the proximal hub 225 and passes through acentral lumen of the outer sheath 22. A second hub member 227, asdepicted in FIGS. 16A and 16B, is coupled to a proximal end of thecatheter body 12. The second hub member 227 and the first hub member 225are removably engageable with each other as will also be describedfurther hereinafter.

Depending upon the orientation of the filter member 16, the first end 18or the second end 20 may either be fixed or moveable relative to thecatheter body 12. Alternatively, as will be discussed furtherhereinafter, the filter member 16 may have only a first end 18 which isfixed to the catheter body 12

To facilitate percutaneous introduction of the inventive CVAF 10, aphysician may optionally elect to employ an introducer sheath (notshown) as vascular access conduit for the CVAF 10. The presence of thefilter member 16 at the distal end of the catheter body 12 creates aregion of relatively lower flexibility and the practitioner maydetermine it beneficial to employ an introducer sheath for vascularaccess.

As used in this application, unless otherwise specifically stated, theterms “proximal” and “distal” are intended to refer to positionsrelative to the longitudinal axis of the catheter body 12. Those skilledin the art will understand that the catheter body 12 has a distal endwhich is first inserted into the patient and a proximal end whichopposite the distal end. Additionally, the terms “inferior” or“inferiorly” are intended to refer to the anatomic orientation of beingin a direction away from the patient's head while the terms “superior”or “superiorly” are intended to refer to the anatomic orientation ofbeing toward the patient's head.

The multi-lumen aspect of the inventive central venous access filtercatheter 10 is shown more clearly in FIGS. 2-5. The catheter body 12 hasa proximal section 13 and a distal section 14. which is longitudinallyopposite the proximal section 13, and which may have a relativelysmaller diametric profile than the proximal section 13. As describedabove, the first lumen 44 terminates at the proximal port 32, while thesecond lumen 42 terminates at the distal port 34. A central guidewirelumen 30 may be provided that extends the entire longitudinal length ofthe catheter body 12 and terminates at the distal end of the catheterbody 12 at a distal guidewire opening 31 that permits the catheter bodyto track along a guidewire during a procedure. The central guidewirelumen 30 may also be used to introduce fluids, such as bioactive agents,intravenous fluids or blood transfusions.

Additionally, at least one of a plurality of infusion lumens 40 areprovided, each having at least one infusion port 36 that passes througha wall of the catheter body 12. Bioactive agents, flushing fluids forflushing or under elevated pressures for mechanical thrombolysis ofthrombus in the filter member 16, contrast agents or other fluids may beinfused through the infusion lumens 40 and out of the at least oneinfusion port 36 to pass into the patient's venous system for eitherlocal or systemic effect. In accordance with one embodiment of theinvention, plural infusion ports 36 are provided with multiple ports 36being provided in communication with a single infusion lumen 40 andspaced along a longitudinal axis of the catheter body 12. Additionally,plural infusion ports 36 may be provided in a circumferentially spacedmanner to provide for fluid infusion at points spaced around thecircumference of the catheter body 12. In this manner, fluid infusion isprovided along both the longitudinal axis and the circumferential axisof the catheter body 12 within the spatial area defined by and boundedby the filter member 16. Because the plural infusion ports 36communicate with the spatial area defined by and bounded by filtermember 16, fluids introduced through the infusion lumens 40 are directedimmediately at thrombus caught within the filter member 16. This permitsthrombolytic agents, high pressure mechanical thrombolysis using apressurized saline flush to be introduced directly to the situs ofthrombus capture within filter member 16. Alternatively, thermal,ultrasound or other types of thrombolysis may be employed to disruptthrombus captured by the filter member 16. For example, the annularspace between the outer sheath 22 and the catheter body 12 may be usedto introduce a thrombolytic to the filter and shower the filter todisrupt thrombus caught by the filter member 16. Additionally, theballoon depicted in FIGS. 21 and 22 may be positioned adjacent thefilter member 16 and be provided with plural openings oriented in thedirection of the filter member 16 to facilitate thrombolysis.

It will be understood, by those skilled in the art, that alternativearrangements of the first lumen 44, the second lumen 42, the guidewirelumen 30, or the infusion lumens are possible and contemplated by thepresent invention. The number and arrangement of lumens in the catheterbody 12 is a function of the desired number of operable ports passingthrough the walls of the catheter body 12, the relative position of theoperable ports, the desired position and geometry of the guidewire lumen30, the desired longitudinal flexibility of the catheter body 12, thedesirable degree of kink resistance of the catheter body 12, and otherfactors which are known to one of ordinary skill in the catheter arts.

While the present invention is not limited to specific dimensional sizesof either the catheter body member 12, the outer sheath 22, lumendiameter or port dimension, an exemplary outer diameter size of theouter sheath 22 is between 8 Fr (2.7 mm) and 9 Fr (3.0 mm) while anexemplary outer diameter size of the catheter member 12 is between 6 Fr(2.0 mm) and 7 Fr. A diametric transition taper 15 may be providedbetween the proximal portion 13 and the distal portion 14 of thecatheter body 12 corresponding to the thickness of the filter member 16.In this manner, the outer surface of the filter member 16 issubstantially co-planar with the outer diameter of the proximal portion13 of the catheter body 12 about its entire circumference.Alternatively, the catheter body member 12 may have a constant diameterand the filter member 16 coupled to an outer surface of the catheterbody member 12, with the outer sheath 22 having a luminal diametersufficient to fit over the filter member 16. Moreover, the fixed firstend 18 of filter 16 is positioned adjacent and in abutting relationshipwith the diametric transition 15, while the moveable second end 20 offilter member 16 is concentrically positioned around the distal section14 of catheter body 12 and is reciprocally moveable thereupon toaccommodate diametric expansion of the filter member 16. Lumen diameterand port dimension are a function of design requirements and arevariable depending upon the desired purpose and function of the lumen orport, e.g., pressure sensing, infusion, evacuation, guidewire, flowsensing, or flow conduit.

In order to aid a physician in visualizing the CVAF 10 in vivo with animaging system 900, at least one radio-opaque or other viewable markermay be provided. A first marker 24 is provided at the distal end of theouter sheath 22 and a second marker 26 may be provided at a distal tip33 of the catheter body 12. It will be understood that when the outersheath 22 is in its non-retracted delivery position, that the filter 16will be covered and the marker 24 and the second marker 26 will beadjacent or in close proximity with one another. Alternatively, theouter sheath 22 may, itself, be made of or include a radio-opaque orother viewable material, such as a metal braid or metal reinforcementwithin or applied to a polymeric sheath. The first and second markers24, 26 or the material of the outer sheath 22 may enhance visualizationof the CVAF 10 under fluoroscopy, ultrasound or other visualization orguidance technique.

FIGS. 6-11 illustrate a second embodiment of the CVAF 50. Unlike CVAF10, CVAF 50 does not include the central guidewire lumen 30 of CVAF 10.Rather, while the general construct of CVAF 50 is similar to that ofCVAF 10, a different configuration of the inner lumens is employed.

CVAF 50, like CVAF 10, consists generally of a multi-lumen centralvenous access catheter body 12 having a proximal port 32 associated witha first lumen 54 and a distal port 34 associated with a second lumen 58,a filter member 16, having a fixed first end 18 and a moveable secondend 20, is positioned generally intermediate the distal port 34 and theproximal port 32 and is generally concentric relative to the catheterbody 12. Use of the term “generally intermediate” is intended to meanthat at least a substantial portion of the filter member 16 residesintermediate the distal port 34 and the proximal port 32. Thus, thefilter member 16 may partially overlay either or both of the proximalport 32 or the distal port 34.

The catheter body 12 has a proximal section 13 and distal section 14,which is longitudinally opposite the proximal section 13 which may havea relatively smaller diametric profile than the proximal section 13. Asdescribed above, the first lumen 54 terminates at the proximal port 32,while the second lumen 58 terminates at the distal port 34. Anatraumatic tip 52 terminates the catheter body 12 at its distal end. Theatraumatic tip 52 preferably includes a radio-opaque marker to aid inpositional visualization of the distal end of the catheter body 12.

A plurality of infusion lumens 56 are provided, each having at least oneinfusion port 36, preferably plural infusion ports 36, that passesthrough a wall of the catheter body 12 and communicates with a spacedefined within an area bounded by the filter member 16. Bioactiveagents, flushing fluids, pressurized mechanical thrombolytic fluids, orother fluids may be infused through the infusion lumens 56 and out ofthe at least one infusion port 36 to pass into the space defined by thefilter member 16 and ultimately into the patient's venous system foreither local or systemic effect. In accordance with one embodiment ofthe invention, the each of the plural infusion lumens 56 are in fluidcommunication with plural ports 36 arrayed along both the longitudinalaxis and the circumferential axis of the catheter body. Thisconfiguration provides for fluid infusion along both the longitudinalaxis and the circumferential axis of the catheter body 12 and in directcommunication with the space defined by the filter member 16 thatcaptures thrombus.

The infusion lumens 56, the first lumen 54 and the second lumen 58 arebounded by and separated from each other by first catheter septum 51 andsecond catheter septum 56 which also aid in providing structural supportfor the catheter body 12. First catheter septum 51 is a generallydiametrically and longitudinally extending member that divides the firstlumen 54 from the second lumen 58 along the longitudinal axis of thecatheter body 12. Second catheter septum 56 may comprise a generallyU-shaped member that intersects the first catheter septum 51 at a loweraspect of the septum and is connected with an inner wall surface of thecatheter body 12 at upper aspects of the septum 51 to define twoinfusion lumens in lateral regions of the catheter body 12.

The filter member 16 has two general configurations. A firstconfiguration consists generally of two opposing generally open conicalsections formed by plural interconnected structural elements definingthe lateral surfaces of each open conical section, wherein the twoopposing generally open conical sections each have open bases facingeach other which are interconnected by a generally cylindrical sectionof the filter member 16. Each open conical section has an open base andan apex, wherein the apices project in opposing directions, with oneapex projecting proximally and another apex projecting distally relativeto the axis of the catheter. The plural interconnected structuralelements forming the lateral surfaces of each generally open conicalsections may be strut-like structural members extending generallyaxially along the longitudinal axis of the filter member 16. The axiallyextending strut-like structural members may be linear members or may becurved members. The apices of each of the generally open conicalsections are formed either of a generally cylindrical collar that servesto couple the filter member 16 to the catheter body 12. The generallycylindrical collar is concentrically engaged about the catheter body 12and may be axially movable thereupon, or is formed by connectionsbetween adjacent pairs of longitudinal strut-like structural memberswhich circumscribe a circumference of the catheter body 12. Thegenerally cylindrical section of the filter member 16 is formed by agenerally open lattice of interconnected structural elements whichconnect the base of a first open conical section to the base of a secondopen conical section. The generally cylindrical section of the filtermember 16 lies in apposition with a vascular wall upon deployment of thefilter member 16 with a vascular lumen.

A second general configuration of the filter member 16 consistsgenerally of a single generally open conical section in which aplurality of longitudinal strut-like structural members form the lateralsurfaces of the conical section and are connected to a generallycylindrical collar which couples the filter member 16 to the catheterbody 12 at an apex of the generally open conical section. The base ofthe generally open conical section is formed by opposing ends of thelongitudinal strut-like structural members. A generally cylindricalsection of the filter member 16, formed of a generally open lattice ofinterconnected structural elements, extends from the longitudinalstrut-like structural members forming the base of the generally openconical section, to provide a region of the filter member 16 which is inapposition to the vascular wall upon deployment of the filter member.

One embodiment of the filter member 16 is illustrated in itsdiametrically expanded configuration in FIGS. 12-13D. In thisembodiment, filter member 16 consists generally of a first end 18 and asecond end 20, each of which consists generally of a tubular structurewhich is circumferentially positioned about a section of the catheterbody 12. One of the first end 18 and second end 20 are fixedly coupledto the catheter body 12, while the other is movable relative to thecatheter body 12. At least one of a plurality of first strut members 62,are coupled at their first end to the first end 18 of filter member 16and each extends axially relative to the longitudinal axis of thecatheter body 12. Each of the first strut members 62 is an elongatemember that, upon diametric expansion of the filter member 16, flaresaway from the central longitudinal axis of the catheter body 12, in agenerally tapered conical manner, and terminates in an end section 63that bends generally parallel to and along the longitudinal axis of thecatheter body 12. A plurality of second strut members 64 are coupled atan end to the second end 20 of filter member 16 and each extendsparallel relative to the longitudinal axis of the catheter body 12. Aplurality of third strut members 66 are coupled at ends thereof to thean end of the filter member and each extends parallel relative to thelongitudinal axis of the catheter body 12. It will be appreciated, bythose skilled in the art, that the number of struts employed as thefirst strut members 62, the second strut members 64 and the third strutmembers 66 forming the filter member 16 may be evenly distributed abouta 360 degree circumference and define the lateral wall surfaces of thefilter member 16. A circumferential member 70 extends circumferentiallyto define a circumferential axis of the filter member 16 and has aseries of continuous undulations defining peaks a series of peaks 75 andvalleys 77 about the circumference of filter member 16. Each of theplurality of first strut members 62, the plurality of second strutmembers 64 and the plurality of third strut members 66 are coupled tothe circumferential member 70 at different points about itscircumferential axis and intermediate the proximal end 18 and the distalend 20 of the filter member 16. In its unexpanded state the filtermember 16 has a generally tubular shape, while in its expanded state thefilter member 16 assumes one of the general configurations discussedabove, i.e., either oppositely extending generally open conical sectionsor a single generally open conical section.

The plurality of first strut members 62 are preferably offset from eachother by approximately 120 degrees about the circumference of thecatheter body 12. The plurality of second strut members 64 are alsopreferably offset from each other by approximately 120 degrees. Finally,the plurality of third strut members 66 are also preferably offset fromeach other by approximately 120 degrees. Each of the plurality of firststrut members 62 couple at a junction 76 to the circumferential member70 at a peak thereof. Similarly, each of the plurality of third strutmembers 66 couple at junction 76 to the circumferential member 70 at apeak thereof. In this manner, a first strut member 62 and a third strutmember 66 are each coupled to circumferential member 70 at junction 76and, in this relationship, form a generally linear member that extendsalong the longitudinal axis of the catheter body and connects betweenthe proximal end 18 of the filter member 16 and the distal end 20 of thefilter member 16. Each of the second strut members 64 couple, at theirproximal ends to a valley 77 of the circumferential member 70 andconnects at a junction 79. Unlike the connections at junction 76 betweenthe plurality of first strut members 62 and the plurality of secondstrut members, in this embodiment of the filter member 16, there is nomember that connects to junction 79 and extends from the first end 18 ofthe filter member 16. In this configuration, the circumferential member70 assumes a generally circumferential tri-leaflet ring having threepeaks 75 and three valleys 77 which circumferentially circumscribe acentral opening 72 which faces inferiorly relative to the patient'sblood flow such that the blood flow first passes into the centralopening 72 and past the third strut members 66 and the second strutmembers 64 then past the first strut members 62.

To facilitate bending and folding of the circumferential member 70between the expanded and unexpanded states, generally U-shaped hingemembers 74 may be provided at each of the valleys 77 of thecircumferential member 70. It will be understood that each of theplurality of first strut members 62, plurality of second strut members64, plurality of third strut members 66 and the circumferential member70 are preferably fabricated of biocompatible materials, such as shapememory alloys, superelastic materials or elastic materials, including,without limitation, titanium, vanadium, aluminum, nickel, tantalum,zirconium, chromium, silver, gold, silicon, magnesium, niobium,scandium, platinum, cobalt, palladium, manganese, molybdenum and alloysthereof, such as zirconium-titanium-tantalum alloys,cobalt-chromium-molybdenum alloys, nitinol, and stainless steel.

FIGS. 14A-14H and corresponding FIGS. 15A-15H depict alternativeembodiments of the filter member 16, labeled 80, 90, 100, 110, 120, 130,140 and 150, respectively. Like filter member 16, each of filter members80, 90, 100, 110, 120, 130, 140 and 150 having a first end 18 and asecond end 20 that each consist of a generally ring-like structureintended to circumferentially couple to a catheter body 12 (not shown),with the first end 18 being fixed and the second end 20 beingreciprocally moveable axially along the distal portion 14 of catheterbody 12. Like filter member 16, each of the alternative filter memberembodiments depicted in FIGS. 14A-14H and 15A-15H, consist of aplurality of first strut members 81, 91, 101, 111, 121, 131, 141 and151, respectively, extending distally from the first end 18 of thefilter member and a plurality of second strut members 83, 93, 103, 113,123, 133, 143 and 153, respectively, extending proximally from thedistal end 20 of the filter member, with a diametrically expansiblecircumferential member 87, 97, 107, 117, 127, 137, 147, 157,respectively, interconnecting the distally extending strut members 81,91, 101, 111, 121, 131, 141 and 151, respectively, with the proximallyextending strut members 83, 93, 103, 113, 123, 133, 143 and 153. In thealternative embodiments of filter members 100, 110 and 120, at leastsome distally extending strut members and at least some of theproximally extending strut members form linear elements that extendalong the entire longitudinal axis of the respective filter member, withthe circumferential member being comprised of at least one undulating orserpentine ring structure.

In the alternative embodiments of filter members 80, 90, 130, 140 and150, a plurality of distally extending strut members are provided spacedapproximately 120 degrees apart from one and other about thecircumference of the filter members, and the distally extending strutmembers bifurcating once or twice distally in a generally Y-shapedmanner as in filter members 80, 130, 140 or 150, or the proximallyextending strut members bifurcating proximally in a generally Y-shapedmanner and interconnecting with the distally extending generallyY-shaped strut members to form a diamond-like pattern as in filtermember 90. In filter members 90 and 140, the circumferential member isformed by the diamond-like pattern formed by the intersection of theplurality of struts. In contrast, in filter members 80, 130 and 150, thecircumferential member is formed by at least one undulating orserpentine ring structure which is diametrically expansible. Asillustrated in filter members 110, 120 and 130, apical portions of eachundulating or serpentine ring structure is interconnected by aninterconnecting member 114, 124, 134, respectively, either with anadjacent ring structure, as in filter member 110 or to a distal end 20of the filter member itself. A longitudinally serpentine section 132 infilter 32 may be provided in conjunction with the interconnecting member134, to afford greater expansive properties to the circumferentialmember 137.

According to some embodiments particularly well-suited for placement byfemoral or other infrarenal approach, the filter member 16 ischaracterized by a generally conical filter member 16 having a greateropen surface area exposed to the flow of embolic material into thefilter at its proximal end, while the distal end has smaller opensurface area exposed to the flow of embolic material to capture theembolic material in the distal end of the filter member.

In other embodiments particularly well-suited for placement by a jugularor suprarenal approach, the filter member 16 is characterized by agenerally conical filter member 16 having a greater open surface areaexposed to the flow of embolic material into the filter at its distalend, which the proximal end of the filter member 16 has a smaller opensurface area exposed to the flow to capture smaller embolic material inthe distal end of the filter member 16.

Additionally, in all of the embodiments the filter member 16 isself-centering to provide proper apposition against the vascular wallsand centering within the lumen of a blood vessel. This maximizes theflow dynamics of the filter member 16 within the blood vessel forpurposes of capturing embolic material within the struts of the filterand centers the catheter body member 12 within the vascular lumen.

As noted above, the proximal 32 and distal 34 ports serve as means formeasuring flow rates or pressure differentials across the filter 16.This may be accomplished by including flow sensors and/or pressuretransducers 19 in operable association with each port 32, 34, with theassociated electrical connections to the flow sensors an/or pressuretransducers 19 passing through the respective lumens associated witheach port 32, 34 and terminating at the proximal end of the catheterbody 12. Where flow sensors 19 are employed, a single flow sensorassociated with proximal port 32, the distal port 34 or the distal endof outer sheath 22 may be sufficient to detect fluid flow rate at theposition of the catheter body 12. By providing a flow sensor at thedistal end of sheath 22, the clinician will be able to determine flowvelocity at the distal end of the outer sheath 22 prior to introducingthe catheter body 12 and make fine adjustments to the placement of thedistal end of the outer sheath 22 to ensure proper placement for thefilter member 16. Plural flow sensors 19 may be employed and operablyassociated with each of proximal port 32 and distal port 34 to sensechanges in flow velocity across the filter member 16. Alternatively, theflow sensors and/or pressure transducers 19 may reside in communicationwith the lumens respectively associated with each port 32, 34 at theproximal end of the catheter body 12, thereby eliminating the need forelectrical connectors resident with the associated lumens. Furthermore,wireless flow sensors and/or pressure transducers may be provided incommunication with each port 32, 34, and be operably coupled to a powersource and a transmitter to wirelessly transmit telemetry data from thetransducers to a wireless receiver in communication with thetransmitter, as is known in the art.

Alternatively, the proximal 32 and distal ports 34 may be used formonitoring or sensing other conditions in the body that are detectablein the blood. For example, analyte sensors may be introduced to eitherthe lumens communicating with the proximal 32 or distal ports 34 or tothe ports themselves to monitor and/or sense chemical or biochemicalconditions in the body. An example of this application is monitoring orsampling blood glucose levels for diabetes control. Further, theproximal 32 and distal ports 34 may be used for fluid infusion or forwithdrawal or evacuation of fluids or other material through thecatheter body 12. In this later instance, where the proximal port 32 ispositioned to underlay the filter member 16, thrombus collected in thefilter member 16 may capable of being lysed, either by thrombolysisthrough the infusion ports 36 or under the influence of thermal ormechanical lysis, such as by introducing a laser, ultrasound or othersystem capable of lysing thrombus, which may be introduced through thelumen communicating with the proximal port 32, or the distal port 32 orthe guidewire lumen 30, or introduced separately from the CVAF 10,positioned within the space bounded by the filter member 16, lysingthrombus collected in the filter member 16 and evacuating the lysedthrombus through the proximal port 32

It is known that flow rate increases proximally within the venoussystem. For example a flow rate of 1 L/min is typical in one femoralvein, increases to 2 L/min in the inferior vena cava and increasinganother 0.7 to 1 L/min proximate the renal veins. Knowing the typicalflow velocities in vessels of different transverse cross-sectionalareas, coupled with a flow sensor 19 associated with the multi-lumencatheter body 12 may serve to supplement or replace the requirements forfluoroscopy or sonography in placement of the CVAF 10, 50.

Other sensors, such as, for example, chemosensors, color sensors,electrical sensors or biosensors, may be employed in lieu of or inaddition to pressure transducer and/or a flow sensor 19 in order todetect other changes or conditions within the patient's vasculature. Forexample, color sensors exist that sense color changes in thrombus, suchcolor changes may be displayed and interpreted by the medicalpractitioner as an indication of thrombus staging. Analyte sensors, sucha as a glucose sensor or an oxygen saturation sensor may also beemployed.

The filter member 16, or its alternative embodiments described above,may be fixed to the catheter body 12 or may be removably coupled to thecatheter body 12 for deployment as either a permanent filter or as atemporary and retrievable vena cava filter. Removable coupling of thefilter member to the catheter body 12 may be accomplished with a varietyof release and retrieval mechanisms operably associated the catheterbody 12 and proximate the diametric transition 15. Non-limiting examplesof such release and retrieval mechanisms include a wire release thatengages with a the first end 18 of the filter, a cooperating indexeddetent and projection interaction between the catheter body 12 and thefirst end 18 of the filter, such as a detent in the proximal end of thefilter and a cooperating projection in the multi-lumen catheter that ispositionally indexed to the detent and releasable from the detent, or,alternatively, a helical slot or threads may be formed in the proximalend 18 of the filter and indexed and cooperating projection in themulti-lumen catheter than permits engagement and disengagement with thehelical slot or threads.

In use, an introducer sheath is first placed into the body in a normalmanner for introducing a central venous line, such as by the Seldingertechnique. Specifically, after accessing a vein using a large boreneedle, under local anesthesia, a guidewire is inserted through theneedle bore and passed into the vein. Once the guidewire is positioned,the needle is withdrawn, and a dilator together with the introducersheath introduced over the guidewire. Once the introducer sheath ispositioned at a desired location within the venous system underradiography, the dilator may be removed from the patient. Radiopaquemarkers associated with the introducer sheath may be employed to assistin positional visualization of the distal end of the introducer sheath.The outer sheath 22 covering the filter 16 is removed while introducingthe filter member 16 and catheter body 12 into the introducer sheath.The outer sheath 22 constrains the filter member 16 during its passagethrough the introducer sheath and positioning the distal end of thecatheter within the patient's vasculature. Once the distal end of thecatheter body 12 reaches the distal end of the introducer sheath, thefilter is deployed. If the filter therapy alone is desired, the filtermember 16 is detached from the catheter body 12 and the catheter body12, introducer sheath and guidewire is withdrawn from the patient. Whereboth central venous access and filter therapy is desired, the introducersheath and catheter body 12 with the filter member 16 is left in thepatient until withdrawal is required.

Retrieval and removal of a detached filter member 16 is accomplishedusing a second procedure under local anesthesia which substantiallyreplicates the placement of the CVAF, with a capture sheath (not shown),similar to introducer sheath, being introduced, a retrieval catheterbeing introduced through the sheath, and engaging the filter member 16,then withdrawn into the capture sheath to collapse the filter member 16,with the entire assembly of the filter member 16, catheter body 12,outer sheath 22 and guidewire, if used, is withdrawn from the patient.

As depicted in FIGS. 16A and 16B, which depict the undeployed state(FIG. 16A) and the deployed state (FIG. 16B) of the filter member 216,respectively, common to each of the embodiments of the present invention200 is an inner catheter 214 that carries the vena cava filter 216 at adistal end thereof. The inner catheter 214 is concentrically andreciprocally engaged within an outer sheath 222 such that relative axialmovement of the inner catheter 214 and the outer sheath 222 eitherexposes the vena cava filter 216 for deployment or captures the venacava filter 216 for retrieval. A first hub member 225 is coupled to aproximal end of the outer sheath 222 and a second hub member 227 iscoupled to a proximal end of the inner catheter 214. First hub member225 and second hub member 227 are engageable, such as by a threaded,bayonet, snap fit, friction fit or interference fit fitting, to securethe inner catheter 214 within the outer sheath 222 and restrict relativeaxial movement of the two elements after deployment of the vena cavafilter 216. A flush line 229 communicates with the first hub member 225and is in fluid communication with a luminal space within the outersheath 222. A plurality of fluid lines 231, 233, 235, 237 communicatewith the second hub member 227 and are each in fluid communication withone of the plural lumens within the inner catheter member 214, e.g.,lumens communicating with the proximal, distal or infusion ports (notshown). A distal tip 26 is provided at a distal end of the innercatheter.

A jugular approach necessitates that the catheter be introducedretrograde relative to the vector of blood flow within the vena cava,i.e., the catheter is introduced through the jugular vein and directedinferiorly toward an infrarenal position. Additionally, since the bloodflow opposes the distal end of the catheter and passes toward theproximal end, the vena cava filter must open inferiorly such that itslargest diametric section in apposition to the vessel walls opens towardthe distal end of the catheter rather than toward the proximal end ofthe catheter as with the femoral approach.

FIGS. 17-20 depict alternative embodiments of vena cava filter membersin accordance with the present invention. FIG. 17 illustrates a filterorientation for a femoral approach, while FIGS. 18-20 illustrate afilter orientation for a jugular approach. As illustrated in FIG. 17,filter member 216 defines a relatively larger volume open space 201 anda relatively smaller volume open space 203. Open spaces 201 and 203 arebounded by structural members of the filter member 216 and are both opentoward the direction of blood flow indicated by arrow 5, with largeropen space 201 being relatively upstream the blood flow relative tosmaller open space 203 in both the femoral or the jugular orientation offilter member 216.

As with all previous embodiments described of the filter member, filtermember 216 is formed of plural interconnected structural elements. Inaccordance with the preferred embodiments of the filter members of thepresent invention, and as particularly exemplified by filter member 216,the filter member has a first end 218 and a second end 220, at least oneof which is attached to the distal section 214 of the catheter body 212.First structural members 217 extend generally axially, either proximallyas shown in FIG. 17 or distally as shown in FIG. 18, along thelongitudinal axis of the filter member 216. Again, it is understood thatuse of the terms “proximal” or “proximally” and “distal” or “distally”are intended to refer to positions relative to the longitudinal axis ofthe catheter body 212. The first structural members 217 are connected toeither the first end 218 or the second end 220 of the filter member 216.Second structural members 219 are connected to the first structuralmembers 217 at an end of the first structural members 217 which isopposite that connected to either the first end 218 or the second end220 of the filter member 216. In accordance with a preferred embodimentof the invention, the second structural members 219 form at least twosuccessive zigzag shaped structures which are connected to an end of thefirst structural members and at opposing apices 223 to form conjoinedring-like structures about the circumference of the filter member 216.In this manner the second structural members 219 generally definelattice-like pattern upon diametric expansion of the filter member 216.The lattice-like pattern formed by the second structural members 219projects axially along the longitudinal axis of the catheter 214tapering to form at least one petal-like projection 225 that terminatesin an terminal apex member 227. As will be appreciated by those skilledin the art, FIG. 17 depicts three petal like projections 225, with onebeing behind the plane of the figure and, therefore, not shown. Each ofthe petal-like projections 225 act to engage and oppose vascular wallsurfaces to seat the filter member 216 against the vessel wall, andcenter the filter member and catheter 214 within the vascular lumen. Asillustrated in FIG. 17, third structural members 221 are provided andare connected to each of the terminal apex members 227 and extendaxially relative to the catheter 214 and connect with a second end 218of the filter member 216.

In the embodiment illustrated in FIG. 17, which is an orientation of thefilter member 216 for a femoral approach, and in the embodimentillustrated in FIG. 19, which is an orientation of the filter member 216for a jugular approach, the first end 218 of the filter member 216 isfixedly connected to the catheter 212, while the second end 220 of thefilter member 216 is movably coupled to the catheter 212 and movesaxially along the catheter 216 upon expansion or contraction of thefilter member 216.

FIG. 18 depicts an embodiment of the filter member 216 identical to thatillustrated in FIG. 19, with the sole exception that the thirdstructural members 219 and the second end 220 of the filter member 216are omitted. In this embodiment, the terminal apex member 227 of eachpetal-like member 225 are not connected to a second end 220 of thefilter member 216 by the third structural members 219.

FIG. 20 depicts an alternative embodiment of the filter member 216 whichis similar to that depicted in FIG. 18, except that at least onecircumferential ring member 252 is connected to the terminal apex member227 of each of the petal-like members 225 at a juncture 253 with theterminal apex member 227. The addition of the additional circumferentialring member 252 results in a relative elongation over the length L1 ofthe filter member 216 depicted in FIG. 18 by a length L2 whichfacilitates additional apposition between the filter member 216 and thevascular wall and stabilization of the petal-like members 225.

FIGS. 21A and 21B depict an alternative embodiment of the filter member216 in FIG. 18, having first end 318, first structural elements 317 andsecond structural elements 319 all analogously arranged as in theembodiment of FIG. 18. Filter member 300, however, employs a modifieddistal end 314 of the catheter 312 to include an expansive balloon 360.The guidewire lumen of the multi-lumen catheter 312 may be used in placeof a distal port for either condition sensing, flushing, infusion or thelike. The expansive balloon 360 may be used to break up thrombuscaptured within the filter member 316, either by mechanical forcethrough serial dilatation or by infusion of a thrombolytic agent throughopenings in the balloon 360. FIG. 21A depicts the balloon 360 in itscollapsed state, whereas FIG. 21B depicts the balloon in its expandedstate.

Alternatively, an expansive balloon 360 may be placed proximal thefilter member 300 and serve to temporarily occlude the vessel tofacilitate aspiration or evacuation of thrombus from the filter member30.

Finally, FIGS. 22A and 22B depict an alternative embodiment of thefilter member 216 in FIG. 20 having first end 418, first structuralelements 417 and second structural elements 419, at least onecircumferential ring member 452 connected to the terminal apex member427 of each of the petal-like members 425 at a juncture 453 with theterminal apex member 427; all analogously arranged as in the embodimentof FIG. 20. Filter member 400, however, employs a modified distal end414 of the catheter 412 to include an expansive balloon 460. Theguidewire lumen of the multi-lumen catheter 412 may be used in place ofa distal port for either condition sensing, flushing, infusion or thelike. The expansive balloon 460 may be used to break up thrombuscaptured within the filter member 416, either by mechanical forcethrough serial dilatation or by infusion of a thrombolytic agent throughopenings in the balloon 460. FIG. 22A depicts the balloon 460 in itscollapsed state, whereas FIG. 22B depicts the balloon in its expandedstate.

Again, an expansive balloon 460 may be positioned proximal the filtermember 416 to permit temporary occlusion of the blood vessel and permitaspiration or evacuation of thrombus from the filter member 416.

It will be appreciated by those skilled in the art that in allembodiments of the described central venous access filter, the filtermember has a relatively larger opening that is open inferiorly in adirection that opposes the blood flow vector and employs structuralelements that taper superiorly along the direction of the blood flowvector to reduce the open surface area of the filter member and capturethrombus.

Thus there has been described a central venous access filter inaccordance with the foregoing embodiments of the invention whichinclude, generally, a multi-lumen catheter body, a filter member and anintroducer sheath. The multi-lumen catheter body has a plurality ofports each of which are in fluid flow communication with at least onelumen in the multi-lumen catheter body. Lumens may include a centralguidewire lumen useful for tracking over a guidewire and/or largervolume infusion of bioactive agents, intravenous fluids, bloodtransfusions, or other fluids; infusion lumens in communication withinfusion ports positioned to direct fluids to the space bounded by thefilter member for introducing bioactive agents, including thrombolyticagents or flushing agents, including pressurized fluids for mechanicalthrombolysis directly to the capture site of the thrombus in the filtermember; and lumens communicating with proximal and distal ports whichmay also be used for fluid introduction and/or may house or communicatewith sensors, such as pressure transducers, flow sensors, analytesensors, color sensors, optical sensors or the like. The filter membermay be detachable from the multi-lumen catheter body to permit temporaryfilter placement and later retrieval by a detachment mechanism thatcooperates between the filter and the multi-lumen catheter body. Theseand other aspects of the present invention are provided by way ofnon-limiting examples, with the claims appended hereto serving to definethe scope of the subject matter regarded as the invention.

What is claimed is:
 1. A method of capturing thrombus within a bloodvessel, comprising the steps of: introducing a multi-lumen catheterhaving a filter member coupled thereto, wherein the filter member iscircumferentially coupled about a distal region of the multi-lumencatheter and has a first end coupled circumferentially in fixed relationto the multi-lumen catheter and a second end circumferentially moveablycoupled to the multi-lumen catheter, the filter member consisting of: aplurality of struts configured to form a generally frustroconicalproximal section of the filter member tapering proximally and havingproximal interstitial openings, and a generally frustroconical distalsection of the filter member tapering distally and having distalinterstitial openings, the frustroconical proximal section having alength that is greater than or less than a length of the frustroconicaldistal section, each of the proximal interstitial openings having anopen surface area either greater than or less than the open surface areaof each of the distal interstitial openings; where the filter member isconfigured to expand in a patient's blood vessel such that a transversedimension of the filter decreases in the direction of the patient'sblood flow to collect thrombi, wherein the vena cava filter membercenters the multi-lumen catheter within a blood vessel lumen; deployingthe multi-lumen catheter within a blood vessel such that the filtermember expands so that the larger interstitial openings between thefrustroconical distal or proximal sections open facing a patient's bloodflow; inserting an ultrasound imaging system operable to detect acondition of the filter member into a lumen of the multi-lumen catheterand positioning the ultrasound imaging system in a region of themulti-lumen catheter bounded by the filter member; and imaging thefilter member with the ultrasound imaging system, wherein the conditionof the filter member is the presence of a thrombus in the filter member.2. The method according to claim 1, wherein the step of imaging thefilter member further comprises confirming the presence of a thrombuscaptured within the filter member.
 3. The method according to claim 1,wherein the ultrasound imaging system is configured to be deployed byinsertion into a lumen of the multi-lumen catheter to permit imagingwithin a region bounded by the filter member.
 4. The method according toclaim 3, wherein the step of inserting the imaging system into the lumenof the multi-lumen catheter further comprises disposing an imaging tipin a region of the multi-lumen catheter bounded by the filter member. 5.The method according to claim 1, wherein the step of imaging the filtermember further comprises imaging the filter member from within themulti-lumen catheter; and infusing a fluid through at least one lumen inthe multi-lumen catheter in communication with at least one infusionport passing through a sidewall of the multi-lumen catheter and open toan inner spatial area bounded by the filter member.
 6. A multi-lumenvena cava filter catheter, comprising: a catheter body having a firstlumen and a second lumen, the first lumen and the second lumen beingseparated by a portion of the catheter body, the catheter body alsohaving a first distal opening in communication with the first lumen anda second distal opening in communication with the second lumen, whereinthe first distal opening is disposed a first distance proximally from adistal end of the catheter body and the second distal opening isdisposed a second distance proximally from the distal end of thecatheter body; a vena cava filter member circumferentially coupled abouta distal end of the central venous line catheter body and having a firstend coupled circumferentially in fixed relation to the central venousline catheter body and a second end circumferentially moveably coupledto the central venous line catheter body, the vena cava filter memberconsisting of a plurality of struts configured to form a generallyfrustroconical proximal section of the vena cava filter member taperingproximally and having proximal interstitial openings, and a generallyfrustroconical distal section of the vena cava filter member taperingdistally and having distal interstitial openings, the frustroconicalproximal section having a length that is greater than or less than alength of the frustroconical distal section, each of the proximalinterstitial openings having an open surface area either greater than orless than the open surface area of each of the distal interstitialopenings; the vena cava filter member being positioned generallyintermediate the first distal opening and second distal opening andconfigured to be expanded in a patient's blood vessel such that atransverse dimension of the filter decreases in the direction of thepatient's blood flow to collect thrombi, wherein the vena cava filtermember centers the central venous line catheter body within a bloodvessel lumen; and an ultrasound imaging system operable to detect acondition of the filter, wherein the condition of the filter member isthe presence of a thrombus in the filter member.
 7. The medical deviceaccording to claim 6, wherein ultrasound imaging system is configured tobe deployed by insertion into a lumen of the multi-lumen catheter topermit imaging within a region bounded by the filter member.
 8. Themedical device according to claim 7, wherein the imaging system isconfigured to image the filter member in situ.
 9. The medical deviceaccording to claim 6, wherein the imaging system further comprises animaging core, a drive cable, and an imaging tip.
 10. The medical deviceaccording to claim 9, wherein the imaging tip is adapted to bepositioned within the multi-lumen catheter body in a region bounded bythe filter member.
 11. A multi-lumen vena cava filter catheter,comprising: a catheter body having a first lumen and a second lumen, thefirst lumen and the second lumen being separated by a portion of thecatheter body, the catheter body also having a first distal opening incommunication with the first lumen and a second distal opening incommunication with the second lumen, wherein the first distal opening isdisposed a first distance proximally from a distal end of the catheterbody and the second distal opening is disposed a second distanceproximally from the distal end of the catheter body; a vena cava filtermember circumferentially coupled about a distal end of the centralvenous line catheter body and having a first end coupledcircumferentially in fixed relation to the central venous line catheterbody and a second end circumferentially moveably coupled to the centralvenous line catheter body, the vena cava filter member consisting of aplurality of struts configured to form a generally frustroconicalproximal section of the vena cava filter member tapering proximally andhaving proximal interstitial openings, and a generally frustroconicaldistal section of the vena cava filter member tapering distally andhaving distal interstitial openings, the frustroconical proximal sectionhaving a length that is greater than or less than a length of thefrustroconical distal section, each of the proximal interstitialopenings having an open surface area either greater than or less thanthe open surface area of each of the distal interstitial openings; thevena cava filter member being positioned generally intermediate thefirst distal opening and second distal opening and configured to beexpanded in a patient's blood vessel such that a transverse dimension ofthe filter decreases in the direction of the patient's blood flow tocollect thrombi, wherein the vena cava filter member centers the centralvenous line catheter body within a blood vessel lumen; and a sheathhaving an outer wall surface and an inner wall surface, the sheathconfigured to be movably disposed over the catheter body and the venacava filter member such that the sheath is longitudinally displaceablerelative to the catheter body to deploy the vena cava filter member; andan ultrasound imaging system operable to detect a condition of thefilter, wherein the condition of the filter member is the presence of athrombus in the filter member.
 12. The medical device according to claim11, wherein the ultrasound imaging system is configured to be deployedby insertion into a lumen of the multi-lumen catheter to permit imagingwithin a region bounded by the filter member.
 13. The medical deviceaccording to claim 12, wherein the imaging system is configured to imagethe filter member in situ.
 14. The medical device according to claim 11,wherein the imaging system further comprises an imaging core, a drivecable, and an imaging tip.
 15. The medical device according to claim 14,wherein the imaging tip is adapted to be positioned within themulti-lumen catheter body in the region bounded by the filter member.